Menthol, the substance we can smell
in mentholated cough drops, is composed of C, H, and O. A
0.1005-g sample of menthol is combusted, producing 0.2829 g
of CO2 and 0.1159 g of H2O. What is the empirical formula
for menthol? If menthol has a molar mass of 156 g/mol, what is its molecular formula?.
The empirical and molecular formulas are C 10H20O
2. Homework Equations
Whole-number multiple = molecular weight /empirical formula weight
The Attempt at a Solution
Cant arrive at the same answer. I started off using the masses of the combustion products, in the case of carbon
(0,2829 g CO2 ) (mol CO2 /44,0 g CO2) (mol C/mol CO2) =
0,00643 mol C
As for H and O, I got 0,129 mol and 0,00643 mol respectively. Then comparing the relative number of moles of each element
C: 0,00643/0,00643=1 H: 0,129/0,00643=20 O:0,00643/0,00643 = 1 lead me obtaining CH20O as the empirical formula. What am I doing wrong?